Lawn-trimmer.



0. H. WATKINS.

LAWN TRIMMER.

APPLICATION FILED JUNE 1, 1909.

Patented May 3, 1910.

2 SHEETS-SEEET l.

0. H. WATKINS.

LAWN TRIMMER. APPLIOATION FILED JUNE 1, 1909.

956,654. Patented May 3,1910.

2 SHEETS-SHEET 2.

ORLA H. WATKINS, OF AMES, IOWA.

LAWN-TRIMMER.

Specification of Letters Patent.

Patented May 3, 1910.

Application filed June 1, 1909. Serial No. 499,300.

To all whom it may concern:

Be it known that I, OKLA H. WATKINS, a citizen of the United States,residing at Ames, in the county of Story and State of Iowa, haveinvented a certain new and useful Lawn-Trimmer, of which the followingis a specification.

The object of my invention is to provide a lawn trimmer of simple,durable and inexpensive construction, and especially designed fortrimming the edges of a lawn and for cutting grass around trees, bushes,or other objects.

A further object is to provide simple, durable, and easily operatedmeans for operating the oscillating cutting blade. 7

A further object is to provide a device of this kind in which thetraction wheel may be moved in a circle, the center of which is at theouter edge of the cutting blade, and the cutting blade will be actuatedduring the entire movement of the traction wheel around said circle sothat the cutting blade may be placed close to a small bush or otherobject and the traction wheel moved in a circle around the same, and thegrass will be cut all around and close to the bush or other object.

My invention consists in the construction, arrangement and combinationof the various parts of the device whereby the objects contemplated areattained, as hereinafter more fully set forth, pointed out in my claims,and illustrated in the accompanying drawings, in which- Figure 1 shows atop plan View of a complete lawn trimmer embodying my invention withparts broken away to show certain de tails of construction. Fig. 2 showsa detail, perspective view illustrating the connection between the crankshaft and the oscillating cutter blade. Fig. 3 shows a detail side Viewillustrating the gearing devices. 1 shows a side elevation of the deviceembodying my invention and taken from the side opposite that shown inFig. 3; and Fig. 5 shows a detail view illustrating the ratchet clutchdevice for throwing the oscillating cutter blade out of gear when thetraction wheel is moved backwardly.

Referring to the accompanying drawings, the main frame of the device iscomposed of a hollow casing 10 in which the gear wheels, hereinafterdescribed, are contained. Extended laterally from the rear of the casing10 and then forwardly is an arm 11 having,

Fig.

at its outer end, the stationary cutter blades: 12. The central portionsof these stationary cutting blades are arranged approximately in theperpendicular plane passing through the axis of the supporting wheel forpurposes hereinafter made clear. Pivoted to the gear casing 10 is aplate 13 to which the handle 14 is attached. This plate 13 is providedwith a slot 15 and a bolt 16 is fixed to the gear casing 10 and passedthrough said slot to limit the pivotal movement of the handle relativeto the casing.

Mounted in the central portion of the casing is an. axle 17 on which thetraction wheel 18 is mounted. This traction wheel is provided with aninternal gear 19. R0- tatably mounted in the casing 10 is a shaft 20having rotatably mounted thereon a pinion 21 in mesh with the gear teeth19 and also having fixed thereon a large pinion 22.

Formed on the pinion 21 is a ratchet wheel 23 and slidingly mounted onthe shaft 20, adjacent to the ratchet wheel 23, is a ratchet wheel 24normally held by a spring 25 in position in engagement with the ratchetwheel 23. This ratchet device is for the purpose of causing the pinion22 to rotate only when the traction wheel is moving forwardly.

Mounted in the casing 10 is a shaft 26 having thereon a small pinion 27in mesh with the large pinion 22. Said shaft is extended laterally overthe arm 11 to a bearing 28 and on the outer end of the shaft is a crank29 having a crank pin 30 fixed thereto.

Mounted upon the outer end of the arm 11 is an oscillating cutter blade31 pivotally connected to the arm 11 by means of the bolt 32. Theforward end of the cutting blade 31 is provided with teeth 33 to co-actwith the teeth 12. Mounted upon the cutter blade 31 is a guide devicecomprising an upright 34: having a slot 35 therein to receive the crankpin 30. The arrangement of these parts is such that the crank pin 30 isso arranged with relation to the pivotal center of the cutting blade 31that, if extended, it would intersect a line perpendicular to said bladeat said pivotal center. Therefore, when the shaft 26 is rotated, thecrank pin 30 will operate upon the guide 34 in such a manner as tooscillate the cutting blade 31, there being sufficient play between thecrank pin and the slot to prevent binding movements. The shape of theouter end of the arm 11 is such that the oscillating cutter blade 31will not project beyond the arm at any portion of its stroke. In thisway, the oscillating cutter blade is protected from striking againstobjects adjacent to the side of the cutter blade.

In practical use, it is obvious that the operator may graspthe handleand have the traction wheel 18 resting upon the ground, and he then may,by means of the handle, either permit the inner end of the arm 11 torest upon the ground, or he may hold it at any desired elevation abovethe ground so that he may cut grass at any desired distance from theground. When the trimmer is being advanced in a straight line over theground, the cutting blade 31 will be oscillated ata comparatively highspeed by means of the gearing devices, and when the trimmer is movedrearwardly, the cutter blade will not be operated as the spring actuatedratchet clutch device will permit the traction wheel to move withoutoperating the cutting blade.

One of the most important advantages in connection with the use of mylawn trimmer is that it will cut grass easily and efliciently all arounda small object such, for instance, as a bush. In doing this, theoperator places the inner end of the arm 11 close to, or even against,the bush or other object, and then moves the traction wheel in a circlearound the object. The central portions of the cutting blades arearranged substantially in the perpendicular plane passing through theaxis of the traction wheel so that when the traction wheel is movedaround in a circle, centered at the inner end of the cutting blades, thecutting blades need not be advanced while the traction wheel is movingin a circle around them and yet the upper blade will be oscillatedduring such movement. It is obvious that if the central portions of thecutting blades were arranged either in front of or in the rear of a linethrough the axle of the traction wheel, the above mentioned result couldnot be accomplished and it would be impossible to cut grass close arounda small bush in the manner described.

I claim as my invention.

1. In a device of the class described, the combination of a frame, ahandle connected to the frame, a traction wheel in the frame, a shaftextended laterally from the frame,

means interposed between the traction wheel and the shaft for impartinga rotary movement to the latter, a horizontally disposed cutter bladefixed to the frame and extended laterally under the shaft and thenforwardly and provided at its forward edge with cutter teeth, thecentral portions of said teeth being substantially in the perpendicularplane passing through the axis of the traction wheel, an oscillatingcutter blade mounted upon the stationary one having teeth thereon toco-act with the stationary teeth, a crank on said shaft, a crank pin onthe crank arranged in such position that, if extended, it wouldintersect a line perpendicular to the pivotal point of the oscillatingcutter blade, a slotted guide in the oscillatinp' cutter blade toreceive said crank pin, substantially as and for the purposes stated.

2. In a device of the class described, the combination of a framecomprising a gear casing, 21 horizontally disposed stationary cutterplate extended laterally from one side of the gear casing and thenforwardly and having cutter teeth formed on its forward end, a handleconnected to said frame, an axle mounted in the gear casing, a tractionwheel fixed to said axle and having an internal gear, a shaft rotatablymounted in the casing, a pinion thereon to mesh with the internal gear,a larger pinion onthe same shaft contained within the gear casing,aspring actuated ratchet device for permitting the traction wheel toturn rearwardly without turning the last mentioned pinion, a shaftmounted in the frame, a small pinion on the shaft in mesh with the lastmentioned large pinion, a crank on said shaft, a crank pin fixed to thecrank and inclined in a direction, which, if extended, would intersect aline perpendicular to the central )ortion of the stationary cutterplate, an osci lating cutter plate mounted on the stationary one, aslotted guide on the oscillating cutter plate to receive said crank pin,the cutter teeth on said stationary and oscillating plates beingarranged with their central portions substantially in the perpendicularplane passing through the axis of the traction wheel, substantially asand for the purposes stated. r Des Moines, 1a., Apr. 1, 1909.

ORLA H. lVATKINS. ll itiiesses RALPH Onwlo, MILDRED B. GOLDIZEN.

